'Look at all the BONES...' 

Addition of Animal bones into a Bloomery Iron Smelt
 
June 20, 2020
Wareham, Ontario

Smelt Team:
Neil Peterson, Rey Cogswell
Smelt Master : Darrell Markewitz

ABSTRACT

    Several recent papers have suggested the presence of small fragments of bone sometimes found within the debris fields related to bloomery iron smelting point to a possible 'ritual' practice, even so far as proposing a functional impact on iron bloom quality. How might the physical process within a complete iron making sequence effect the ability of bone to endure, and thus remain to be recovered archaeologically? A typical 'short shaft' furnace will be constructed and operated through to bloom extraction on a clean working surface. Both bone pieces and meat containing bone of several animal types will be added, before, during, at at the final stage of the smelting process. Afterwards, the debris field will be examined in detail to determine what remains of the bones.


Imaging the Smelt

The majority of these images were taken by Kelly Probyn-Smith (2020)

rough
starting
Initial fill with rough charcoal Smoke from incomplete combustion
ignition
repair
Complete ignition, 'starting ritual' (1) Additional clay attempting to seal extraction arch
venting
tapping
Continued venting as fresh clay contracts First (deliberate) slag tap (about + 2 hours)
incontinent
incontinent2
Self tap, base opposite tuyere
Second, considerably larger, self tapping
instructions
arch1
Rey Cogswell prepares for extraction
Starting by removing clay at extraction arch
breaking probe
Breaking clear the front of the slag bowl
Using a heavy bar to loosen the slag bowl
reaching
extracted
Reaching in for the loosened slag mass
Mass pulled free!
hammering
bloom
Initial compaction to a flat cake
Boom pieces, compacted and segmented
slag bowl
t slag
Pieces of slag bowl re-assembled, position where the bloom hd been located clearly visible.
Hardened tap slag , removed from the front of furnace



Notes :

1) Over the years the development of several 'smelting rituals' have been observed.
Some of these have started as practical jokes on one of the participants, some with a much more serious intent (echoing those known from the few remaining 'traditional' practices. from Africa or Japan).
The DARK team cooks a batch of 'Jiffy' popcorn, at the point the furnace self ignites gases at the top, first burning completely. Over the years this 'smelter corn' has proved a fairly reliable indicator of the probable end result of a smelting effort.

unless otherwise credited - Text and photography Darrell Markewitz